1. Field of the Invention
This invention relates generally to an apparatus and method for the minimally invasive treatment and ablation of tissue masses such as tumors, and more particularly to a tissue surface treatment apparatus with independently deployable electrodes configured to controllably ablate a tumor proximate or beneath a tissue surface.
2. Description of the Related Art
Standard surgical procedures, such as resection, for treating benign and malignant tumors of the liver and other organs have several key shortcomings affecting efficacy, morbidity and mortality. In an effort to fully remove or resect the tumor, the surgeon may be forced to remove or injure healthy tissue, compromising the function of the target organ. Further, the surgeon must exercise care in not cutting the tumor in a manner that creates seeding of the tumor, resulting in metastasis and spread of the disease. Also surgical resection procedures are contraindicated for instances of diffuse disease and/or small amounts of remaining healthy tissue.
Ablative treatment methods such as radio-frequency ablation, cryo-ablation, and microwave ablation have been employed as an alternative to resection to treat benign and malignant tumors in organs such as the prostate. However, these therapies in their present form have several critical drawbacks including: (i) inability to ablate/necrose the entire tumor; (ii) inability to ablate or necrose tissue along the entire length/perimeter of the tumor margin; (iii) inability to reduce lesion size sufficiently to reduce pain levels; (iv) inability to treat smaller tumors without potentially damaging surrounding healthy tissue and/or critical organs and structures; (v) inability of introducer to deploy device at an angle or otherwise access difficult to reach tumors; and (vi) inability to determine a meaningful clinical endpoint. In particular tumors lying near or underneath an organ surface present a distinct set of problems to current ablative therapies. In order to superficially treat these types of tumors it is desirable for the physician to be able to deliver ablative treatment into the tumor, while avoiding all together or minimizing injury to critical anatomical structures that are adjacent and/or underneath the target tumor mass.